Monday, November 28, 2005

The Aerodynamics of Insect Flight

Here is a very cool article on the aerodynamics of insect flight, which was reporting the results (and associated background) of a new PNAS paper by Caltech professor Michael Dickinson and colleagues. Dickinson does very nice work, but he is unfortunately one of those experimentalists who seems to like to slam theorists at every opportunity. He did it in a seminar I saw him give, and he and his coauthors wrote the following in their paper:

"Since this time," the authors note, "bees have symbolized both the inadequacy of aerodynamic theory as applied to animals and the hubris with which theoreticians analyze the natural world."

Modern theoretical work on insect flight is predominantly computational in nature. (One faculty member at Cornell, Jane Wang, has done a lot of excellent work in this area. I first became aware of this problem at the job interview she gave at Cornell during my first year there.) In fact, the associated numerics are extremely difficult, which is one reason why there was confusion years ago about scientists predicting that insects can't fly. Models that don't model the wings as continua (and use rigid body dynamics instead) don't do the job here, so the problem of insect flight is much more difficult than that of airplane flight. This is an unsteady aerodynamics problem with a fluid (the air) coupled to deformable solids (the wings), and very intense computions (that challenge the current technology enormously---let alone what used to be available) are required to deal with it.

Anyway, this is one of the topics in fluid mechanics that I find really neat. I've never done any work in it and have many other things on my list so I can't say that I ever will, but this is definitely one where it's especially cool to keep abreast of how scientific understanding is developing.

10 comments:

  1. The group dynamics is really interesting too, as the simplest translation into physics is a nearest neighbor coupling model. but, I cannot help but noticing the Insect theme again :) -jing

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  2. Ugh, that's a bad sign. Clearly, I must repent.

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  3. no worries, you can always take comfort in knowing that i _choose_ to use MS Word for thesis writing. -j.

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  4. OK, so we both need to repent.

    Choosing MS Word for thesis writing seems like a migraine waiting to happen. I still say that's a turn-off. :) It's perfectly fine for your cover letter, however.

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  5. So, Mason, where does PNAS fall in the journal spectrum?

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  6. Basically, that depends on whether one is a biologist or not.

    My biologist friends tell me that the acronym stands for "Post Nature and Science" or "Probably Not Accepted to Science", so for those guys it's not considered as good as it is for people in other fields.

    Nature and Science have very few physics papers and even fewer applied math/math papers, so PNAS has a very good reputation in such fields. The type of article it's really good for are ones that combine disciplines that aren't usually mixed. It was perfect for my Congress paper, for example, because I'm never going to get a poly sci person to read a PRL article and it was important to get this in a journal where they would see it. (This is indeed what has transpired, although it would be inappropriate for me not to mention that I did try Nature and Science first. However, poly sci people actually are far more likely to read PNAS than the other two, so I should have started with PNAS.) The downside of PNAS is that the articles are really short by nature, so it is necessary to subsequently write an archival person of one's work for a journal that allows longer papers. In the case of Congress, I believe we'll be submitting to Social Networks. (We waited because we wanted to add a lot of stuff and do new things rather than just writing a longer version of what we had already done.)

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  7. PNAS has different track of submission and it CAN publish paper without peer review. I remain suspicious if the paper is not Track II (peer reviewed) submission. - jing

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  8. Jing is absolutely correct. I meant to include this comment in my response. I wouldn't bother submitting to PNAS via track I because people (possibly most people) will very sensibly be suspiscious of it, and rightly so.

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  9. My advisor really wants to submit something under Track 1, though I will try to dissuade him in this case. (We are interested in...timely...publication.) Why does that option exist?

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  10. I think Track I exists for the Academy members who just don't want to deal with peer review. The problems from the suspiscion mentioned above comes not for them but rather for their junior colleagues (like you). Basically, I think it would selfish of your advisor to do Track I, because he has to be aware that it can hurt you.

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